Plot horizon distance from ranking statistics

This MR will change the horizon distance plotting program in the DAG: instead of creating one horizon distance plot from reference PSDs, the new program create the horizon distance from the ranking statistic for each template bank bin. The main changes that affect the DAG workflow are summarized below:

• gstlal_inspiral_pipe: change plotting program from gstlal_plot_psd_horizon to gstlal_inspiral_plot_rankingstats_horizon (previously called gstlal_inspiral_plot_psd_horizon which does not accurately describe what it actually does, also see miscellaneous changes below).
• inspiral.py: update the horizon_dist_layer for the new plotting program.
• gstlal_inspiral_summary_page: horizon distances plots are put inside a new UI component (report.ImagePagination) so that all the plots will not be fetched at the same time and can be paginated.
• make the above changes to new style DAG workflow as well.

Miscellaneous changes:

• add new plotting module called horizon.py
• update the gstlal_plot_psd_horizon to use horizon.py module,
• renamed gstlal_inspiral_plot_psd_horizon --> gstlal_inspiral_plot_rankingstats_horizon

Note: this MR depends on gstlal-visualisation/ligo-scald!36 (merged), it's better not to merged before that request has been merged.

gstlal-inspiral/bin/gstlal_inspiral_plot_rankingstats_horizon

+#!/usr/bin/env python3
+#
+# Copyright (C) 2021  ChiWai Chan
+#
+# This program is free software; you can redistribute it and/or modify it
+# under the terms of the GNU General Public License as published by the
+# Free Software Foundation; either version 2 of the License, or (at your
+# option) any later version.
+#
+# This program is distributed in the hope that it will be useful, but
+# WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General
+# Public License for more details.
+#
+# You should have received a copy of the GNU General Public License along
+# with this program; if not, write to the Free Software Foundation, Inc.,
+# 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+
+"""Plot horizon history from ranking statistics.
+
+"""
+
+from itertools import groupby
+from optparse import OptionParser
+from pathlib import Path
+
+from gstlal.plots import horizon
+
+from lal.utils import CacheEntry
+
+def parse_command_line():
+	usage = "Usage: %prog [options] file1 file2 ..."
+	parser = OptionParser(description = __doc__, usage = usage)
+
+	parser.add_option("-o", "--outdir", default = ".", help = "Set the output directory. By default, current directory will be used.")
+	parser.add_option("-f", "--format", default = "png", help = "Set the output format. By default, the output will be a png file.")
+	parser.add_option("-s", "--fig-size", default = "12,4", help = "Set the output figure size in inch. By default, the figure size will be 12,4. (Optional)")
+	parser.add_option("-v", "--verbose", action = "store_true", help = "Be verbose. (Optional)")
+
+	options, args = parser.parse_args()
+	options.format = options.format.strip(".")
+	try:
+		figsize = options.fig_size.split(",")
+		w, h = float(figsize[0]), float(figsize[1])
+	except:
+		raise ValueError("Please provide valid --fig-size, expecting a format of 'width,height', got '%s'." % options.fig_size)
+	else:
+		options.fig_size = (w, h)
+
+
+	if len(args) == 0:
+		raise ValueError("Must provide at least one ranking statistics file.")
+
+	return options, args
+
+options, files = parse_command_line()
+
+urls = []
+for f in files:
+	if f.endswith(".cache"):
+		urls.extend([CacheEntry(line).url for line in open(f)])
+	elif f.endswith(".gz"):
+		urls.append(f)
+
+outdir = Path(options.outdir)
+for key, group in groupby(sorted(urls, key = lambda x: CacheEntry.from_T050017(x).description), lambda x: CacheEntry.from_T050017(x).description):
+	rankfiles = list(group)
+	ce = CacheEntry.from_T050017(rankfiles[0])
+	title = f"Horizon Distance for Bin {ce.description.replace('_MARG_DIST_STATS', '')}"
+	desc = ce.description.replace('MARG_DIST_STATS', 'HORIZON')
+	start = ce.segment[0]
+	duration = ce.segment[1] - ce.segment[0]
+	output = outdir / f"{ce.observatory}-{desc}-{start}-{duration}.{options.format}"
+	horizon_distance = horizon.HorizonDistance.from_rankingstats(rankfiles, verbose = options.verbose)
+	horizon_distance.savefig(output, figsize = options.fig_size, title = title)